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[hot_ride]

So I got my ///M 261 wheels with the stock RFTs on today for the first time. Less than 2 kms out I hit a pothole and the sensor went off. Of course thinking that I got a flat I went to a local tire shop. When I got there I visually inspected the tires and none appeared flat. I used a pressure gauge and again none appeared flat. Called BMW to find out how to reset the sensor. Reset it and no more issues...

Anyone else have this happen? I just put these suckers on, how often is this going to spook me?

[ZIPNBYE]

Don't hit the potholes...a simple plan that will save you un-neccesary wheel alignments and with the RFTs, possilbly a bent wheel too.

[ptack]

Ha, my baby is still at the dealer today because they couldn't get the sensor to turn off after the took my snows off. They said they may have to replace the whole module. To me the whole thing is a stupid gimmick that I would be just as happy not paying for.

[warmtoes]

First thing is that if you are in Canada we do not have TPMS we have TPW which is a flat monitoring system that uses rotational differences in the tires.

If all it takes is a quick reset which you can do yourself I wouldn't worry about it. I have hit some big potholes and have not had this happen.

[gnpower]

Originally Posted by hot_ride

So I got my ///M 261 wheels with the stock RFTs on today for the first time. Less than 2 kms out I hit a pothole and the sensor went off. Of course thinking that I got a flat I went to a local tire shop. When I got there I visually inspected the tires and none appeared flat. I used a pressure gauge and again none appeared flat. Called BMW to find out how to reset the sensor. Reset it and no more issues...

Anyone else have this happen? I just put these suckers on, how often is this going to spook me?

Mine cries wolf nearly everytime it gets cold. I'm thinking of removing them.

[cagekicker]

watch those potholes.

[jeremyc74]

Originally Posted by gnpower

Mine cries wolf nearly everytime it gets cold. I'm thinking of removing them.

This has been covered several times in this forum, but here it is again.

There are two reason you get TPMS warnings.

1 - The system isn't working right. In that case have the dealer fix it
2 - The air pressure in your tires has dropped below the threshold set in the TPMS.

In case number two the fix is VERY simple. Check the air in the tires and make sure they're at the right pressure while it's cold, then reset the system. Problem solved.

In this day of cell phones and computerized everything, I'm a little bit amazed that so many people have such a hard time with something this simple.

[hot_ride]

Originally Posted by jeremyc74

This has been covered several times in this forum, but here it is again.

There are two reason you get TPMS warnings.

1 - The system isn't working right. In that case have the dealer fix it
2 - The air pressure in your tires has dropped below the threshold set in the TPMS.

In case number two the fix is VERY simple. Check the air in the tires and make sure they're at the right pressure while it's cold, then reset the system. Problem solved.

In this day of cell phones and computerized everything, I'm a little bit amazed that so many people have such a hard time with something this simple.

Jeremy,
Good answer, but as mentioned above it is not really a Pressure Monitoring system but a rotation monitoring system. I'm not sure how cell phones and everything being computerized would tell me that the system misfired and gave me the wrong information. I have also never had run flats and am still not sure what a flat would visibly look like. But thanks for your 2 cents. Your change? 2 cents.

ZIPNBYE,
LOL, I wouldn't drive over them if I could avoid them Unfortunately there are A LOT and I can't always be watching the ground or avoid them due to other obstacles.

warmtoes,
What does TPW stand for? I do realize that we have a different system, that is why the subject says "Canadian version". I started the thread to make others aware, but I was also wondering if this is something that happens a lot. You can imagine my disappointment when I was led to believe that I had a flat only 1.5km after putting on my summer rims and tires for the first time.

[jeremyc74]

Originally Posted by hot_ride

Jeremy,
Good answer, but as mentioned above it is not really a Pressure Monitoring system but a rotation monitoring system. I'm not sure how cell phones and everything being computerized would tell me that the system misfired and gave me the wrong information. I have also never had run flats and am still not sure what a flat would visibly look like. But thanks for your 2 cents. Your change? 2 cents.

.

TPMS = Tire Pressure Monitoring System. It's got a pressure sensor inside each wheel (mounted to the back of the valve stem) sending back real time pressure and temperature information to the ECU. It didn't give him the wrong information. The temperature dropped and the pressure in his tires dropped below its setpoint, and it let him know that.

You can't look at a run flat tire and tell that it's low on air pressure, even if it's completely deflated.

[jeremyc74]

Originally Posted by warmtoes

First thing is that if you are in Canada we do not have TPMS we have TPW which is a flat monitoring system that uses rotational differences in the tires.

If all it takes is a quick reset which you can do yourself I wouldn't worry about it. I have hit some big potholes and have not had this happen.

I don't think rotational monitors can be used with runflat tires.

[TitoSkulls]

Originally Posted by jeremyc74

I don't think rotational monitors can be used with runflat tires.

Apparantly they do. I got a puncture from a piece of scrap metal a week after I got my 135i. The low tire pressure sensor came one shortly after that.

[jeremyc74]

Originally Posted by TitoSkulls

Apparantly they do. I got a puncture from a piece of scrap metal a week after I got my 135i. The low tire pressure sensor came one shortly after that.

That's because there's a pressure sensor inside the tire. The run-flats don't deflate, so there's no way to measure rotational speed differences. You guys have to be getting the same TPMS system we get in the states if you've got run-flats on the car.

[TitoSkulls]

Originally Posted by jeremyc74

That's because there's a pressure sensor inside the tire. The run-flats don't deflate, so there's no way to measure rotational speed differences. You guys have to be getting the same TPMS system we get in the states if you've got run-flats on the car.

I'm actually quite certain the Canadian 135i does not have the TPMS sensors, at least the 2008 doesn't. This has been discusses quite a bit in the Canadian forum as many of us were trying to get ready for winter and were ordering winter wheels.

I purchased a set of wheels and tires sans TPMS sensors from Tire Rack and have had no issues with any warnings about a missing sensor. Gill from Tire Rack can probably back this up, but the indicator seems to be that tires with TPMS sensors have aluminum valve stems and the non-TPMS have rubber ones. This may have changed for the 2009 models, I don't know as I haven't really be keeping up on this issue since I got my wheels.

As for how the rotational sensor works on run flats, that I don't know. My guess is that they are just really good sensors that somehow detect very slight changes in pressure. Someone with a much better understanding of this could probably shed some light on how it works.

Here is the thread when this was discussed previously.
http://www.1addicts.com/forums/showt...highlight=tpms

[Tom K.]

Originally Posted by jeremyc74

That's because there's a pressure sensor inside the tire. The run-flats don't deflate, so there's no way to measure rotational speed differences. You guys have to be getting the same TPMS system we get in the states if you've got run-flats on the car.

Jeremy, check out page 67 of the (non iDrive) 2008 1er manual for "FTM". The "Flat Tire Monitor" system compares rotational speeds and was used by BMW as early as 2003 on the first Z4s - which came with OEM Bridgestone RE 050A RFTs. Although the U.S. manual still lists it, I believe it's only our northern neighbors who still have it, as US cars have the individual (in tire) monitors you have described.

So BMW has been using rotational speed monitoring with run-flats for at least 6 years as a pressure drop in one tire is sensed by the system. The disadvantage is that equal pressure loss in all tires cannot be sensed.

Tom

[BlackjackMulligan]

Originally Posted by gnpower

Mine cries wolf nearly everytime it gets cold. I'm thinking of removing them.

If you do this the light will be on all the time unless you can figure out a way to rig it not to.

[jeremyc74]

Originally Posted by TitoSkulls

I'm actually quite certain the Canadian 135i does not have the TPMS sensors, at least the 2008 doesn't. This has been discusses quite a bit in the Canadian forum as many of us were trying to get ready for winter and were ordering winter wheels.



I purchased a set of wheels and tires sans TPMS sensors from Tire Rack and have had no issues with any warnings about a missing sensor. Gill from Tire Rack can probably back this up, but the indicator seems to be that tires with TPMS sensors have aluminum valve stems and the non-TPMS have rubber ones. This may have changed for the 2009 models, I don't know as I haven't really be keeping up on this issue since I got my wheels.


As for how the rotational sensor works on run flats, that I don't know. My guess is that they are just really good sensors that somehow detect very slight changes in pressure. Someone with a much better understanding of this could probably shed some light on how it works.



Here is the thread when this was discussed previously.

http://www.1addicts.com/forums/showt...highlight=tpms

Originally Posted by Tom K.

Jeremy, check out page 67 of the (non iDrive) 2008 1er manual for "FTM". The "Flat Tire Monitor" system compares rotational speeds and was used by BMW as early as 2003 on the first Z4s - which came with OEM Bridgestone RE 050A RFTs. Although the U.S. manual still lists it, I believe it's only our northern neighbors who still have it, as US cars have the individual (in tire) monitors you have described.

So BMW has been using rotational speed monitoring with run-flats for at least 6 years as a pressure drop in one tire is sensed by the system. The disadvantage is that equal pressure loss in all tires cannot be sensed.

Tom

I stand corrected. My apologies.

I was under the impression that the RFTs required the in-wheel pressure sensors. The Corvettes were forced to go to this when the implemented RTFs back in the day. It must be that BMW has increased the resolution on the ABS wheel speed sensors to the point where they can detect the speed difference even with the run-flats, but if they can do that, I'm surprised they weren't able to meet the US standards which don't specify the method of detection, only that the system must be able to sense a certain amount of pressure drop (it's either 10 or 15% IIRC).

This makes me wonder how much air you have to lose in a RFT before the system warns you you're low. It would also seem to be impossible that the system could be giving false alarms due to cold weather, because all the tires will drop pressure at very nearly the same rate.

Edit: I'm looking back now and I realize that the person I originally responded to (with the cold weather issue) isn't in Canada it seems. Sorry for the confusion.

[warmtoes]

TPMS is only required in the US of A. Everywhere else in the world it's TPW (Tire Pressure Warning) or FTM or whatever acronym they use for rotational differences. I believe it's TPMS in the US because of your laws otherwise it would be the same as everywhere else.

[Tom K.]

Originally Posted by warmtoes

TPMS is only required in the US of A. Everywhere else in the world it's TPW (Tire Pressure Warning) or FTM or whatever acronym they use for rotational differences. I believe it's TPMS in the US because of your laws otherwise it would be the same as everywhere else.

It would make more sense if we required an actual readout of psi for each tire as I've seen on some other (much cheaper) cars. Since the hardware & software is already in place, we might then have something really useful!

Tom

[warmtoes]

Originally Posted by Tom K.

It would make more sense if we required an actual readout of psi for each tire as I've seen on some other (much cheaper) cars. Since the hardware & software is already in place, we might then have something really useful!

Tom

I don't disagree. I was so surprised when I heard it didn't actually give you a numeric reading when you've already gone to the cost of placing the sensors and receiver in the car.